Recent findings published on August 11 in the journal eBioMedicine suggest that selecting the same arm for your Covid-19 booster shot as the one used for your initial vaccine may lead to a more robust immune response.
Martina Sester, a biologist and head of the department of the Institute of Infection Medicine at Saarland University Hospital in Germany, coauthored the study and noted that the inquiry, while seemingly trivial, had not been explored previously. Sester commented on the significance of the study’s results in a news release.
The study harnessed data from 303 individuals who had received both an mRNA vaccine and a booster shot as part of Germany’s vaccination campaign. The analysis conducted two weeks after the administration of the booster revealed that individuals who received both shots in the same arm displayed a notable increase in “killer T cells.”
Laura Ziegler, a doctoral student at Saarland University and coauthor of the study, highlighted that these “killer T cells” play a crucial role in targeting and eliminating specific cells. In cases where the injections were administered in the same arm, 67% of participants exhibited the presence of these cells, compared to 43% of individuals who received injections in different arms.
Dr. William Schaffner, a professor in the Division of Infectious Diseases at Vanderbilt University Medical Center, who was not involved in the study, expressed fascination at the research, noting the scarcity of similar investigations concerning other vaccines. Schaffner pointed out the logical reasoning behind the location of injection impacting the immune response, attributing this phenomenon to the concentration of immune-response cells in local lymph nodes.
These lymph nodes are distributed throughout the body, including areas such as the neck, chest, abdomen, and armpits, according to information provided by the American Cancer Society. This study contributes valuable insights into optimizing Covid-19 booster efficacy and underscores the potential importance of the injection site.